". Supporters of the anti-gay marriage movement ""La Manif Pour Tous\"" (Demonstration for all) hold placards as they gather near the Invalides square in Paris on May 26, 2013 during a mass protest against a gay marriage law. France on May 18 became the 14th country to legalize same-sex marriage after President Francois Hollande signed the measure into law following months of bitter debate and demonstrations. Tens of thousands marched through Paris today to protest a new gay marriage law, with police on high alert amid warnings hardliners could infiltrate the demonstration and cause trouble.   ERIC FEFERBERG/AFP/Getty Images"